使用OSX上的CMake将项目与GLFW3链接时未定义的符号

Question

我正在按照本指南关于如何使用GLFW3和OSake 10.9.1上的CMake构建项目,我遇到了一些麻烦.当我构建实际项目时,我收到以下错误:

$ make
Scanning dependencies of target Graphics
[100%] Building CXX object CMakeFiles/Graphics.dir/graphics.cpp.o
Linking CXX executable Graphics
Undefined symbols for architecture x86_64:
  "_glBegin", referenced from:
      _main in graphics.cpp.o
  "_glClear", referenced from:
      _main in graphics.cpp.o
  "_glColor3f", referenced from:
      _main in graphics.cpp.o
  "_glEnd", referenced from:
      _main in graphics.cpp.o
  "_glLoadIdentity", referenced from:
      _main in graphics.cpp.o
  "_glMatrixMode", referenced from:
      _main in graphics.cpp.o
  "_glOrtho", referenced from:
      _main in graphics.cpp.o
  "_glRotatef", referenced from:
      _main in graphics.cpp.o
  "_glVertex3f", referenced from:
      _main in graphics.cpp.o
  "_glViewport", referenced from:
      _main in graphics.cpp.o
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)
make[2]: *** [Graphics] Error 1
make[1]: *** [CMakeFiles/Graphics.dir/all] Error 2
make: *** [all] Error 2

我的CMakeLists.txt看起来像:

cmake_minimum_required (VERSION 2.8)
project (Graphics)

# The version number.
set (Graphics_VERSION_MAJOR 1)
set (Graphics_VERSION_MINOR 0)

# configure a header file to pass some of the CMake settings
# to the source code
configure_file (
  "${PROJECT_SOURCE_DIR}/GraphicsConfig.h.in"
  "${PROJECT_BINARY_DIR}/GraphicsConfig.h"
  )

# add the binary tree to the search path for include files
# so that we will find GraphicsConfig.h
include_directories("${PROJECT_BINARY_DIR}")

find_package(PkgConfig REQUIRED)
pkg_search_module(GLFW REQUIRED glfw3)
include_directories(${GLFW_INCLUDE_DIRS})

# add the executable
add_executable (Graphics graphics.cpp)
target_link_libraries(Graphics ${GLFW_STATIC_LIBRARIES})

# add the install targets
install (TARGETS Graphics DESTINATION bin)
install (FILES "${PROJECT_BINARY_DIR}/GraphicsConfig.h"        
         DESTINATION include)

但是可以很好地使用构建项目

cc `pkg-config --cflags glfw3` -o graphics graphics.cpp \
    `pkg-config --static --libs glfw3`

Answer 1

我无法向您解释为什么一个与 OpenGL 库链接而另一个不链接，但以下解决方案对我在 OSX（Mountain Lion）上遇到类似问题有效。

在“添加可执行文件”块的末尾，添加 Apple 特定条件以与 OpenGL 框架链接：

# add the executable
add_executable (Graphics graphics.cpp)
target_link_libraries(Graphics ${GLFW_STATIC_LIBRARIES})

if (APPLE)
  target_link_libraries(Graphics "-framework OpenGL")
endif()

我认为 GLFW CMake 配置中一定有一些东西负责与 OpenGL 库链接，所以我查看了GLFW 3.0.4 CMakeLists.txt并发现了“-framework”行。

这只会在 OSX 上对您有帮助 - 您需要提供其他平台特定的链接方式以使其跨平台。

您可能已经考虑过它，但同一指南还提供了一种将 GLFW 源包含在您的应用程序中并以这种方式构建它的方法。这可能是保证跨平台兼容性的最简单方法。